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Modeling and Analysis of Scatterometry Signatures for Optical Critical Dimension Reference Material Applications



Heather J. Patrick, Thomas A. Germer, Michael W. Cresswell, Richard A. Allen, Ronald G. Dixson, Michael R. Bishop


We use an optical critical dimension technique, matching modeled to measured scatterometry signatures, to obtain critical dimension linewidth on grating targets fabricated using the single-crystal critical dimension reference materials process. The targets are fabricated on a SIMOX (separation by implantation of oxygen) substrate; we compare experimentally obtained reflectance signatures for the unpatterned substrate with modeled signatures using Fresnel theory and show that the oxide layer is not well described by a single layer of SiO2, but can be well described if a mixed Si/SiO2 boundary layer is included between the Si wafer and the oxide. We then obtain line width from optical critical dimension measurements on a series of grating targets with a range of design line widths and pitches, and show that the line width obtained from optical critical dimension is linearly related to the line width obtained from scanning electron microscopy, with a slope of 0.98 and zero offset. While these results are very promising, further work in improving the fit of the simulated signatures to the measured signatures for some of the targets, reducing the target line roughness, and analyzing the uncertainties for potential optical critical dimension reference materials is anticipated.
Conference Dates
March 27-29, 2007
Conference Title
AIP Conference Proceedings


critical dimension metrology, optical critical dimension, scatterometry, semiconductors, SIMOX


Patrick, H. , Germer, T. , Cresswell, M. , Allen, R. , Dixson, R. and Bishop, M. (2007), Modeling and Analysis of Scatterometry Signatures for Optical Critical Dimension Reference Material Applications, AIP Conference Proceedings, [online], (Accessed July 23, 2024)


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Created May 7, 2007, Updated February 17, 2017